Mother's food allergy warning: 'We almost killed our son'

New advice to GPs in England is published on Wednesday to help them spot young children who may have food allergies.

Harris Berthelson, 11, has had a severe nut allergy all his life and has to carry medicine at all times.

His mother, Alison Berthelson, recounts the story of the day her then two-year-old son nearly died.